The assignee of the present application, The Boeing Company, is a leading innovator in the design of high performance, low cost, compact phased array antenna modules. The Boeing antenna module shown in FIGS. 1a-1c have been used in many military and commercial phased array antennas from X-band to Q-band. These modules are described in U.S. Pat. No. 5,886,671 to Riemer et al and U.S. Pat. No. 5,276,455 to Fitzsimmons et al, both being hereby incorporated by reference.
The in-line first generation module was used in a brick-style phased-array architecture at K-band and Q-band frequencies. This approach is shown in FIG. 1a. This approach requires some complexity for DC power, logic and RF distribution but it provides ample room for electronics. As Boeing phased array antenna module technology has matured, many efforts made in the development of module technology resulted in reduced parts count, reduced complexity and reduced cost of several key components of these antenna modules. Boeing has also enhanced the performance of the phased array antenna with multiple beams, wider instantaneous bandwidths and greater polarization flexibility.
The second generation module, shown in FIG. 1b, represented a significant improvement over the in-line module of FIG. 1a in terms of performance, complexity and cost. It is sometimes referred to as the “can and spring” design. This design provides dual orthogonal polarization in an even more compact, lower-profile package than the in-line module of FIG. 1a. The can-and-spring module forms the basis for several dual simultaneous beam phased arrays used in tile-type antenna architectures from X-band to K-band. The can and spring module was later improved even further through the use of chemical etching, metal forming and injection molding technology. The third generation module developed by the assignee, shown in FIG. 1c, provides an even lower-cost production design adapted for use in a dual polarization receive phased array antenna.
Each of the phased-array antenna module architectures shown in FIGS. 1a-1c require multiple module components and interconnects. In each module, a relatively large plurality of vertical interconnects such as buttons and springs are used to provide DC and RF connectivity between the distribution printed wiring board (PWB), ceramic chip carrier and antenna probes.
A further step directed to reduce the parts count and assembly complexity of the antenna module as described above is described in pending U.S. patent application Ser. No. 09/915,836, “Antenna Integrated Ceramic Chip Carrier For A Phased Array Antenna”, hereby incorporated by reference into the present specification This application involves forming an antenna integrated ceramic chip carrier (AICC) module which combines the antenna probe (or probes) of the phased array module with the ceramic chip carrier that contains the module electronics into a single integrated ceramic component. The AICC module eliminates vertical interconnects between the ceramic chip carrier and antenna probes and takes advantage of the fine line accuracy and repeatability of multi-layer, co-fired ceramic technology. This metallization accuracy, multi-layer registration produces a more repeatable, stable design over process variations. The use of mature ceramic technology also provides enhanced flexibility, layout and signal routing through the availability of stacked, blind and buried vias between internal layers, with no fundamental limit to the layer count in the ceramic stack-up of the module. The resulting AICC module has fewer independent components for assembly, improved dimensional precision and increased reliability.
In spite of the foregoing improvements in antenna module design, there is still a need to further combine more functions of a phased array antenna into a single component. This would further reduce the parts count, improve alignment and mechanical tolerances during manufacturing and assembly, improve electrical performance, and reduce assembly time and processes to ultimately reduce phased array antenna system costs. More specifically, it would be highly desirable to substantially reduce or eliminate dielectric “pucks” that need to be used in a completed antenna module, as well as to entirely eliminate the use of buttons, button holders, flex members, cans, sleeves, elastomers and springs. If all of these independent parts could be substantially reduced in number or eliminated, then the primary issue bearing on the cost of the antenna assembly would be the material and process cost of manufacturing the antenna assembly.
For each of the dual polarization antenna modules/systems described above, there are several characteristics used to gauge the effectiveness (i.e., electrical performance) of the design. These characteristics include return loss bandwidth, radiator-to-radiator isolation, insertion loss bandwidth, higher order mode suppression and cross-polarization levels. All of these characteristics affect the overall electrical performance of the antenna module/system. Therefore, it would be highly desirable if these characteristics could be favorably influenced through a new antenna module design which does not involve the use of numerous and/or costly additional components parts, and which further does not significantly complicate the construction of the various antenna module/system designs described above.